The present invention concerns improvements brought to installations for packaging a product in containers closed with a stopper and including in particular a filling machine suitable to fill containers received empty and a stopping machine supplied with stoppers for the closing of the filled containers.
In the packaging installations such as aforementioned, an incident occurring in the supplying of stoppers to the stopping machine may have serious effects on the principal conveying line of the containers, and/or can cause the loss of a substantial number of containers in any state, and/or can cause a substantial loss of the product to be packaged.
This is the case, in particular, in the installations packaging the product in thermoplastic containers (PET for example) which include in line a supply of preforms, a oven for heating the preforms and a blower for the moulding of containers coming from heated preforms, followed by aforementioned filling machine and stopping machine. In this type of installation, an incident occurring in the supplying of stoppers necessitates, for the repairing operation, the stopping of the whole installation. The preforms during heating in the oven and during blowing in the moulds are then lost; moreover, considering the very high temperatures and the thermal inertias, the preforms present in the oven and the blowing moulds risk melting and/or sticking to the walls of the moulds, so that putting the installation back into operation must be preceded by an inspection and a cleaning.
In addition, for installations for packaging in an aseptic environment or packaging of volatile products for example, it is preferable that the stopping occurs as soon as the filling of the container is completed; otherwise the aseptic character of the product may not be ensured or the volatile product disperses: the containers and their contents may not be used and are lost.
Thus, it turns out in practice that numerous incidents in the supply of stoppers occur downstream of the stopping machine (for example two stoppers wedged in each other, poor positioning, etc). These incidents could be detected therefore well before the non usable stopper reaches the stopping device itself and it should then become possible to anticipate the incident at the working level of the rest of the installation and to avoid losses of filling and/or contained product, indeed a damaging of the installation.
The object of the invention is therefore to propose an improvement in the supply of stoppers suitable to avoid aforementioned disadvantages and to make shorter and less expensive, in all its aspects, the stoppage of the installation following a stopper supplying incident.
To this end, an installation such as mentioned in the introduction is characterised mainly, being arranged according to the invention, in that it includes in addition, upstream of the stopping machine, a device for the dynamic storage of stoppers suitable for continuously driving the stoppers with a pre-specified pitch, the number of stoppers simultaneously present in said storage device being at least equal to the number of containers present in a pre-specified part of the installation, control means for supplying stoppers being provided upstream of the dynamic storage device and being arranged to control a device supplying containers located upstream, preferably at the inlet, of aforesaid pre-specified part of the installation, by means of which arrangement whatever container is engaged in the pre-specified part of the installation there corresponds a stopper present in the device for the dynamic storage of stoppers supplying the stopping machine and, in the event of an incident in the supply of stoppers upstream of the dynamic storage device, the supply of containers to said pre-specified part of the installation is controlled while maintaining in operation the terminal part of the installation at least until this incident is over.
There is thus formed, upstream of the stopping device, a buffer reservoir of stoppers which are individualised and of known number, so that risks of incident at this level in the supply of stoppers to the stopping device is considerably reduced and, in the event of an incident upstream of this buffer reservoir, it is then possible to be able to continue to process all the containers present in said pre-specified part of the installation. Preferably, the supply of containers is controlled by interrupting the upstream supply of containers until the incident is over: alternatively, instead of interrupting this supply, the supply of stoppers is regulated by carrying out a controlled sliding or moving back relative to the containers particularly when the moving back involves a small number (one or two for example) of stoppers.
In a possible implementation of the invention the pre-specified part of the installation includes at least the filling machine and the capacity of the device for the storage of stoppers is at least equal to the number of containers simultaneously present between the inlet of the filling machine and the inlet of the stopping machine.
In another implementation, the invention is applied to an in-line installation arranged for the packaging of a product into thermoplastic material containers (for example of PET) and including in particular, upstream of the filling machine, a preform supply unit, an oven for heating the preforms and a blower to produce containers from the heated preforms; in this case aforementioned pre-specified part of the installation includes at least the oven for heating the preforms and the capacity of the device for the storage of stoppers is at least equal to the number of preforms simultaneously present in the oven.
It can, in addition, be very desirable that aforesaid pre-specified part of the installation includes in addition at least the blower and that the capacity of the device for the storage of stoppers is at least equal to the number of containers (preforms, rough cuts or finished containers) present between the inlet of the oven and the outlet of the blower.
Finally, at least for some areas of application (aseptic packaging for example), it can be worthwhile that aforesaid pre-specified part of the installation includes in addition the filling machine and the stopping machine and that the capacity of the device for the storage of stoppers is at least equal to the number of containers (preforms, rough cuts, or empty or filled finished containers) present between the inlet of the oven and the inlet of the stopping machine.
Thus is won the considerable advantage of avoiding a loss of filled but not stopped containers (aseptic filling), a loss of containers during manufacture (blower/in-line filling machine), a cleaning of the hot units (oven, blowing moulds), and finally the completion of the incident can be carried out without stopping the installation: immediately after completion, the supply of containers can be restarted normally.
In a perfected version, the control means for the supply of stoppers are arranged to regulate the supply of stoppers in the event of an incident in the supply of containers (preforms, rough cuts, or finished or filled containers), for example either by blocking the supply of stoppers, or by causing a sliding of the stoppers relative to the containers.
Although the device for the dynamic storage of stoppers can in principle be arranged in any appropriate way, it is however particularly desirable that it extends approximately vertically so as to occupy a minimum vertical projection surface and to not cause an ill-considered increase in the general dimensions of the installation.
According to another of its aspects, the invention also relates to a particularly worthwhile arrangement of a dynamic storage device for a pre-specified number of stoppers intended for the closing of a succession of filled containers, this device being intended to be used in particular in an installation such as aforementioned in the previous paragraph and comprising:
means for supplying stoppers pre-positioned and placed one after the other,
conveyor means moving the stoppers on a trajectory having a length a function of aforesaid pre-specified number of stoppers,
and withdrawal means located at the outlet of said conveyor means to catch the stoppers one by one.
Such a device, arranged according to the invention, is characterised mainly in that the conveyor means include:
a cylinder rotating around a vertical axis and having, on its peripheral surface, a multiplicity of vertical parallel cavities, and
a fixed helicoidal track narrowly surrounding the cylinder over all its height and suitable for supporting stoppers otherwise partially engaged individually in aforesaid respective cavities of the cylinder so as to be driven on the helicoidal trajectory defined by the track when the cylinder rotates,
the number of revolutions of the helicoidal track and the number of vertical cavities constituted on the periphery of the cylinder defining aforesaid pre-specified number of stoppers simultaneously present in the device.
It is understood that, because of the arrangements of the invention, it is possible to constitute a buffer reservoir of stoppers having a capacity which can be very high, as a function of the diameter of the cylinder and of the number of vertical cavities present on the periphery of this, and above all, for a given diameter of the cylinder, a function of its height. In particular, it is possible to constitute a reservoir of a very high capacity although occupying little vertical projection space and therefore of small size. Its structure is simple and requires standard mechanical parts. Its driving, which must be synchronised with that of the stopping device and with the rest of the installation, may not require a specific motorisation and can be obtained by a traditional return movement (chain, belt, etc.).